The present invention relates to methods and systems for accurately detecting encoded data included in audio media data.
There is considerable interest in encoding audio signals for use in audience measurement. In order to estimate what an audience is listening to at a particular time, a listener's environment is monitored for audio signals at regular intervals. If the detected audio signals contain an identification code, the message may then be quickly identified.
Based upon the receipt of identified messages, the rating or popularity of various broadcasts may be estimated. Therefore, it is very important to accurately determine which encoded audio signals have been received.
However, the acoustic characteristics of differing audio environments may vary greatly. As a result, rates for successfully receiving and identifying audio signals in the differing environments can vary significantly. Some environments for instance, may be quite hostile to the accurate detection of encoded messages because there is a large amount of noise or interference. There may also be circumstances in which the encoded message may not be detected because of a dropout in the code. In these cases, only a portion of the identification code may be received.
Therefore, a system is desired with reduced sensitivity to the acoustic environment, which can detect a code in as many differing circumstances as possible despite hostile acoustic conditions.
A system is also desired that can accurately identify the detection of an encoded message, even if only a portion of the message has been received or detected.